JP2020060319A - Small once-through boiler - Google Patents

Abstract

To provide a small once-through boiler capable of simply obtaining a swirl flow effectively utilizing a heat transfer face of the heat absorbing fin by mounting a buffle plate to a heat absorbing fin, and simply adjusting a heat absorption amount by changing the mounting number of buffle plates.SOLUTION: A small once-through boiler 1 includes: a water pipe row 2, in which a space surrounded by plural water pipes 2a is made into a combustion chamber 3 by arranging the water pipes 2a in a circumferential-like shape; a tubular smoke chamber cover 7 for forming an annular combustion gas flow passage 6 covering an outside of the water pipe row 2 and communicating with the combustion chamber 3 between the water pipe row 2 and itself; and plural heat absorbing fins 9 provided at multiple states in a vertical direction at a portion of the water pipe 2a at a downstream side of at least the combustion gas flow passage 6 facing the combustion gas flow passage 6. A buffle plate 10 giving swing force to the combustion gas flowing in the combustion gas flow passage 6 using a mounting pitch in a vertical direction of the heat absorbing fin 9 of the water pipe 2a adjacent to a form of the heat absorbing fin 9 is detachably mounted to the heat absorbing fin 9 at an inclined posture.SELECTED DRAWING: Figure 2

Description

  According to the present invention, an annular upper pipe drawer and a lower pipe drawer are respectively connected to the upper end and the lower end of an annular water pipe array in which a plurality of water pipes are circumferentially arranged and a space surrounded by the water pipes is used as a combustion chamber. And a cylindrical smoke chamber cover is concentrically arranged outside the water pipe row to form an annular combustion gas flow path communicating with the combustion chamber between the water pipe row and the smoke chamber cover. A plurality of heat-absorbing fins were provided in multiple stages in the portion of each row of water pipes facing the combustion gas passage, and the combustion gas generated in the combustion chamber was made to flow into the combustion gas passage and then discharged from the flue. With regard to the improvement of a small once-through boiler, in particular, a swirling force (combustion gas flows along the circumferential direction of the annular combustion gas passage) in the combustion gas flowing in the annular combustion gas passage through a plurality of heat absorbing fins. Baffle plate that gives force) can be detachably attached, and multiple heat By attaching a baffle plate to the collecting fins, a swirl flow (flow of combustion gas along the circumferential direction in the annular combustion gas flow path) that can effectively use the heat transfer surface of each heat absorption fin is easily obtained. In addition, the present invention relates to a small once-through boiler in which the heat absorption amount can be easily adjusted by changing the number of baffle plates attached.

  Conventionally, as the small once-through boiler 20, for example, one having a structure shown in FIGS. 7 to 9 is known.

  That is, in the small once-through boiler 20, as shown in FIGS. 7 to 9, a plurality of vertical water tubes 21a are circumferentially arranged, and an annular water tube row having a space surrounded by the water tubes 21a as a combustion chamber 22. 21 and the adjacent water pipes 21a of the water pipe row 21 are airtightly attached, and a portion except the upper end portions of the adjacent water pipes 21a is closed to form a slit-shaped combustion gas outlet 23 between the upper end portions of the water pipes 21a. The closing round bar 24 to be formed, an annular upper header 25 and a lower header 26 which are connected to the upper end and the lower end of each water pipe 21a of the water pipe array 21 so as to communicate with each other, and cover the outside of the water pipe array 21. A cylindrical smoke chamber cover 28 that forms an annular combustion gas flow path 27 that communicates with the combustion chamber 22 with the water pipe array 21, and a burner 29 disposed above the combustion chamber 22. .

  Thus, according to the small once-through boiler 20, the combustion gas G generated by the combustion of the burner 29 is inverted in the lower part of the combustion chamber 22 to perform reverse combustion, and the combustion gas outlet 23 forms an annular combustion gas flow path. After flowing into the combustion gas passage 27 from the upper side (upstream) to the lower side (downstream) in the combustion gas flow path 27, it is discharged from the flue 30 connected to the lower end of the cylindrical smoke chamber cover 28. It has become.

  In the small once-through boiler 20, since adjacent water pipes 21a are airtightly connected to each other by the closing round bar 24, it takes time and time to assemble the small once-through boiler 20, and the small once-through boiler 20 cannot be manufactured inexpensively. There is a problem to say.

  The small once-through boiler 20 shown in FIG. 10 and FIG. 11 shows the small once-through boiler 20 for solving the above-mentioned problem, and the upper end of each water pipe 21a of the water pipe array 21 is directed toward the outside of the water pipe array 21 by a predetermined angle. The water pipe mounting pitch circle diameter D1 at the upper end of each water pipe 21a connected to the upper pipe header 25 and the water pipe mounting pitch circle diameter D2 at the lower end of each water pipe 21a connected to the lower pipe header 26 are inclined by θ. > D2, and a vertically long inverted triangular combustion gas outlet 23 having an upper end wider than a lower end is formed between adjacent water pipes 21a. In this small once-through boiler 20, the lower ends of the adjacent water pipes 21a are in close contact with each other.

  Since the small once-through boiler 20 shown in FIGS. 10 and 11 does not require the closing round bar 24 to be mounted between the adjacent water pipes 21a, the structure is simple, the assembly is easy, and the cost is low. is there.

  In the small once-through boiler 20 shown in FIGS. 10 and 11, the same members and parts as those of the small once-through boiler 20 shown in FIGS. 7 to 9 are designated by the same reference numerals, and detailed description thereof will be omitted.

  However, in the small once-through boiler 20 shown in FIGS. 10 and 11, since the upper ends of all the water pipes 21a of the water pipe array 21 are inclined outward, the upstream side portion (upper side portion) of the combustion gas flow passage 27 is Since the pressure is narrow and the pressure loss is large, and the combustion gas flow passage 27 gradually widens toward the downstream side (lower side) of the combustion gas flow passage 27 to reduce the pressure loss, the flow of the combustion gas G after reverse combustion is short-circuited. It tends to pass easily (the combustion gas G does not reach the upper portion of the combustion chamber 22 and flows out from the lower portion of the combustion gas outlet 23 to the combustion gas flow passage 27), and the amount of heat recovered from the combustion gas G is small. There is a problem to say.

  The small once-through boiler 20 shown in FIG. 12 and FIG. 13 improves the problem of the small once-through boiler 20 shown in FIG. 10 and FIG. The water pipes 21a in the vertical posture and the water pipes 21a in the inclined posture are alternately arranged so as to be inclined toward the outside of the row 21 by a predetermined angle θ, and a vertically-long inverted triangular combustion gas outlet 23 is formed between the adjacent water pipes 21a. It was done.

  In the small once-through boiler 20 shown in FIGS. 12 and 13, the upstream side portion of the combustion gas passage 27 is slightly wider than the upstream side portion of the combustion gas passage 27 of the small once-through boiler 20 shown in FIGS. 10 and 11. Therefore, the pressure loss is reduced and the combustion gas G is less likely to short-pass.

  In the small once-through boiler 20 shown in FIGS. 12 and 13, the same members and parts as those of the small once-through boiler 20 shown in FIGS. 7 to 9 are designated by the same reference numerals, and detailed description thereof will be omitted.

  The small once-through boiler 20 shown in FIGS. 14 to 18 is provided downstream of the combustion gas passage 27 of each water pipe 21a in order to further improve the efficiency of the small once-through boiler 20 shown in FIGS. 7 to 9, 12 and 13. The heat-absorbing fins 31 are attached in multiple stages to the portion facing the side portion.

  That is, the small once-through boiler 20 shown in FIG. 14 and FIG. 15 has the water pipes 21a above and below the water pipe 21a at the portion facing the downstream side portion of the combustion gas passage 27 of each water pipe 21a of the small once-through boiler 20 shown in FIGS. The heat-absorbing fins 31 are attached in multiple stages in the direction, and the small once-through boiler 20 shown in FIGS. 16 to 18 is located downstream of the combustion gas passage 27 of each water pipe 21a of the small once-through boiler 20 shown in FIGS. In the portion facing the side portion, heat absorbing fins 31 are attached in multiple stages in the vertical direction of the water pipe 21a.

  In the small once-through boiler 20 shown in FIGS. 16 to 18, every other one of the upper ends of the water pipes 21a of the water pipe array 21 is inclined toward the outside of the water pipe array 21 by a predetermined angle θ, and the adjacent water pipes 21a are inclined. Since the blocking round bar 24 attached between them is omitted, there is an advantage that the structure is simple and the assembly is easy and the cost is low, but on the other hand, compared with the small once-through boiler 20 shown in FIGS. 14 and 15. However, since the area of the combustion gas flow path 27 becomes large, it becomes difficult for the combustion gas G to flow along the water pipe 21a and the heat absorption fin 31, and the heat absorption deteriorates. Further, since the area of the combustion gas passage 27 becomes larger as it goes to the downstream side of the combustion gas passage 27, heat absorption becomes worse.

  In the small once-through boiler 20 shown in FIGS. 14 to 18, the same members and parts as those in the small once-through boiler 20 shown in FIGS. 7 to 9, 12 and 13 are designated by the same reference numerals, and their details will be described. Description is omitted.

  In addition to small-sized once-through boilers shown in FIGS. 14 to 18, Japanese Patent Laid-Open No. 2009-198126 (see Patent Document 1) and Japanese Patent Laid-Open No. H02-202 can be used as small-sized once-through boilers in which heat absorbing fins are provided in multiple stages on a water pipe. The ones described in Japanese Patent Application Laid-Open No. 075805 (see Patent Document 2), Japanese Patent Laid-Open No. 2013-057501 (see Patent Document 3) and Japanese Patent Laid-Open No. 2012-167848 (see Patent Document 4) are known.

  That is, the small once-through boiler (multi-tube boiler) of Patent Document 1 is provided with a combustion gas flow space portion having a large flow passage cross-sectional area at a lower portion of an annular combustion gas flow passage and above the combustion gas flow space portion. In the water pipe, a large number of stages of heat absorbing fins are provided in the portion of the water pipe facing the combustion gas flow passage so as to prevent deviation of the combustion gas flow flowing in the combustion gas flow passage.

  However, the small-sized once-through boiler of Patent Document 1 does not have a structure in which the combustion gas swirls in the annular combustion gas flow path, and the combustion gas discharged from the combustion chamber flows along the water pipe in the annular combustion gas flow path. Since it flows, there is a problem that the heat transfer surface of the heat absorbing fin cannot be effectively used.

  Further, in the small-sized once-through boilers (axisymmetric mixed-flow once-through boilers and boilers) of Patent Documents 2 and 3, heat absorbing fins are provided with respect to the axis line of the water pipe in a portion of the water pipe facing the annular combustion gas flow path. The combustion gas is swirled in the annular combustion gas flow path.

  However, since the small once-through boilers of Patent Documents 2 and 3 have a large space between the adjacent heat absorbing fins attached to the water pipe, most of the combustion gas in the annular combustion gas passage is adjacent to the heat absorbing fins. Since it passes through the space between the fins, a swirling flow of the combustion gas is unlikely to occur in the combustion gas passage, and there is a problem that the heat transfer surface of the heat absorbing fin cannot be effectively used.

  If the heat absorbing fins are made larger, the space between the adjacent heat absorbing fins becomes smaller and swirl flow of the combustion gas easily occurs in the combustion gas flow passage, but if the heat absorbing fins are made larger. Another problem is that the heat absorbing fins are overheated by the combustion gas, causing cracks in the water pipe due to thermal stress.

  Also, the swirling force of the combustion gas in the combustion gas passage can be adjusted by changing the attachment angle of the heat absorption fin to the water pipe. It is necessary to customize the device (fin projection welding device) for attaching the heat absorption fins to the water pipe by changing the welding surface shape of the absorption fins to the water pipe, and it is very time-consuming and costly. Will lead to soaring prices.

  Further, the small once-through boiler of Patent Document 4 has a gas guide plate formed in a spiral shape in an annular combustion gas flow path, and heat absorption without heat absorption fins provided along the gas guide plate. A fin missing zone is provided so that the combustion gas is swirled in the annular combustion gas passage by the gas guide plate.

  However, in the small once-through boiler of Patent Document 4, the width of the gas guide plate is formed to be the same as the width of the annular combustion gas flow path, and the outer diameter of the water pipe is equal to the outer edge and the inner edge of the gas guide plate. Since the semicircular cutouts are formed according to the pitch of the water pipes, it is extremely difficult to attach the spirally formed gas guide plate around the circumferentially arranged water pipes.

JP, 2009-198126, A Japanese Patent Laid-Open No. 02-075805 JP, 2013-057501, A JP2012-167848A

  The present invention has been made in view of such a problem, and an object thereof is to provide a heat absorbing fin provided in a water tube in a multi-stage in a vertical direction with a swirling force on a combustion gas flowing in a combustion gas passage. A baffle plate that gives heat can be easily and detachably attached, and by attaching baffle plates to a plurality of heat absorbing fins, the swirling flow of combustion gas that can effectively use the heat transfer surface of each heat absorbing fin It is an object of the present invention to provide a small once-through boiler in which the heat absorption amount can be easily adjusted by changing the number of attached baffle plates.

  In order to achieve the above-mentioned object, a small once-through boiler invention according to claim 1 of the present invention is an annular water pipe array in which a plurality of water pipes are circumferentially arranged and a space surrounded by the water pipes serves as a combustion chamber. , An annular upper and lower pipe headers connected to the upper and lower ends of each water pipe of the water pipe array so as to communicate with each other, and an annular pipe that covers the outside of the water pipe array and communicates with the water pipe array The cylindrical smoke chamber cover that forms the combustion gas flow path, the burner disposed above the combustion chamber, and the vertical direction at least in the portion of the water pipe downstream of the combustion gas flow path that faces the combustion gas flow path. In a small once-through boiler equipped with a plurality of heat absorbing fins provided in multiple stages, the shape of the heat absorbing fin is used for the heat absorbing fin, and the vertical mounting pitch of the heat absorbing fin of the adjacent water pipe is used. And gives a swirling force to the combustion gas flowing in the combustion gas passage. Tsu is characterized in that fitted with full plate detachably in an inclined position.

  The small-sized once-through boiler according to claim 2 of the present invention is the small-sized once-through boiler according to claim 1, wherein the baffle plate is formed of an elastic metal plate in a planar shape of an arc, and the inside of the baffle plate is The central portion is provided with a recessed portion that fits in the heat absorbing fin so that it can be inserted and removed freely while intersecting with the heat absorbing fins. Also, at both ends of the baffle plate, the heat absorbing fins are vertically shifted by at least one pitch. It is characterized in that each of them is provided with a guide portion which is pressed against and fixed to the fin.

  The small-sized once-through boiler according to claim 3 of the present invention is the small-sized once-through boiler according to claim 2, wherein the baffle plate has a concave portion formed in an inner central portion of the baffle plate intersecting the heat absorbing fins. In the state where the guide portions formed at both ends of the baffle plate are pressed against the heat absorbing fins which are vertically shifted at least one pitch of the adjacent water pipes by the elastic force of the baffle plate itself. Each of them is elastically locked, and one of the guide portions is attached to the heat absorbing fin in an inclined posture such that it is higher than the other guide portion.

  The small-sized once-through boiler according to claim 4 of the present invention is the small-sized once-through boiler according to any one of claims 1, 2 and 3, wherein the baffle plate has a plurality of heat absorbing fins with water pipes. It is characterized in that it is removably attached at a predetermined pitch in the vertical direction, and is also detachably attached to the heat absorption fins at a predetermined pitch in the circumferential direction in the annular combustion gas passage. is there.

  The small once-through boiler according to claim 5 of the present invention is the small once-through boiler according to any one of claim 1, claim 2, claim 3 or claim 4, wherein the baffle plate has smoke at its outer peripheral edge. It is characterized in that it is in contact with the inner peripheral surface of the chamber cover and is held and fixed in an appropriate position by the smoke chamber cover.

  The small once-through boiler of the present invention, the heat absorbing fins provided in a multi-stage in the vertical direction in each water pipe, utilizing the mounting pitch in the vertical direction of the heat absorbing fins of the water pipes adjacent to the shape of the heat absorbing fins, Since the baffle plate that gives swirl force to the combustion gas flowing in the annular combustion gas passage is detachably attached in a tilted posture, the gas guide plate that swirls the combustion gas is welded like a conventional small once-through boiler. By using the baffle plate, a baffle plate that gives a swirling force to the combustion gas in the annular combustion gas passage can be easily and easily attached to the heat absorption fin without needing to be fixed to the water pipe by the baffle plate. A swirling flow of combustion gas that can effectively utilize the heat transfer surface of is easily obtained.

Also, in the small once-through boiler of the present invention, the baffle plate is formed of an elastic metal plate in a circular arc shape in a plan view, and the baffle plate can be freely inserted into and removed from the inner center portion of the baffle plate while intersecting the heat absorbing fins. Since the recessed portion that is fitted to the baffle plate is provided, and both end portions of the baffle plate are provided with the guide portions that are pressed and fixed to the heat absorbing fins that are vertically shifted at least one pitch from the adjacent water pipes. , The concave portion of the baffle plate is fitted and locked in a state of intersecting with the heat absorbing fin, and the guide portions at both end portions of the baffle plate are arranged on the heat absorbing fins which are vertically shifted at least one pitch. The baffle plate is elastically locked while being pressed by the elastic force of the baffle plate itself.
As a result, in the small once-through boiler of the present invention, the baffle plate is relatively firmly attached to the heat absorbing fins by its own elastic force, and can be prevented from falling off from the heat absorbing fins. A swirl flow can be reliably and satisfactorily applied to the combustion gas.

  Further, in the small once-through boiler of the present invention, the baffle plate is detachably attached to the plurality of heat absorbing fins at a predetermined pitch in the vertical direction of the water pipe, and in the annular combustion gas passage in the circumferential direction. Since it is arranged at a predetermined pitch and is detachably attached to the heat absorption fins, the heat absorption amount can be easily changed by changing the number of baffle plates mounted in the vertical direction or the number of baffle plates mounted in the circumferential direction. Can be adjusted.

  Further, in the small once-through boiler of the present invention, since the outer peripheral edge of the baffle plate is in contact with the inner peripheral surface of the smoke chamber cover, and the baffle plate is held and fixed in an appropriate position by the smoke chamber cover, the baffle plate absorbs heat. It is possible to reliably prevent the fins from being displaced or dropped.

It is a schematic longitudinal cross-sectional view of a small once-through boiler according to an embodiment of the present invention. It is an AA line expanded sectional view of FIG. It is a front view which shows a part of water pipe row in the state which attached the baffle plate to the heat absorption fin attached to the water pipe of the water pipe row at a fixed pitch up and down. FIG. 3 is an enlarged view of a portion surrounded by a one-dot chain line circle in FIG. 2. It is an enlarged plan view of a baffle plate. It is a front view which shows a part of water pipe row in the state which changed the attachment pitch of the up-down direction of the baffle plate attached to the heat absorption fin. It is a longitudinal cross-sectional view showing an example of a conventional small once-through boiler. FIG. 8 is a sectional view taken along line BB of FIG. 7. FIG. 9 is an enlarged view of a portion surrounded by a one-dot chain line circle in FIG. 8. It is a longitudinal cross-sectional view showing another example of a conventional small once-through boiler. It is CC sectional view taken on the line of FIG. It is a longitudinal cross-sectional view which shows another example of the conventional small once-through boiler. It is the DD sectional view taken on the line of FIG. It is a longitudinal cross-sectional view which shows another example of the conventional small once-through boiler. It is the EE sectional view taken on the line of FIG. It is a longitudinal cross-sectional view which shows another example of the conventional small once-through boiler. It is the FF sectional view taken on the line of FIG. It is an enlarged view of the part enclosed with the dashed-dotted line circle of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 to 4 show a small once-through boiler 1 according to an embodiment of the present invention. The small once-through boiler 1 is a space surrounded by water tubes 2a in which a plurality of metal water tubes 2a are circumferentially arranged. An annular water pipe array 2 having a combustion chamber 3, and an annular upper metal header 4 and a lower metal metal header 5 which are connected to the upper end and the lower end of each water pipe 2a of the water pipe array 2 so as to communicate with each other. A metallic cylindrical smoke chamber cover 7 that covers the outside of the water pipe array 2 and forms an annular combustion gas flow path 6 that communicates with the combustion chamber 3 between the water pipe array 2 and the upper portion of the combustion chamber 3. The burner 8 provided, a plurality of heat absorbing fins 9 provided in multiple stages in the vertical direction on at least the portion of the water pipe 2a on the downstream side of the combustion gas passage 6 facing the combustion gas passage 6, and the heat absorbing fin 9 And a metal bar that is detachably attached to the combustion gas passage 6 and applies a swirling force to the combustion gas G flowing in the combustion gas passage 6. It is provided with a full plate 10, a.

  In FIG. 1, 11 is a refractory material that protects the upper and lower pipe heads 4, 5 and the upper and lower end portions of each water pipe 2a.

  As shown in FIGS. 1 and 2, the ring-shaped water pipe array 2 has a plurality of water pipes 2a arranged in a vertical posture and circumferentially arranged with the outer peripheral surface of the lower end portion of the water pipes 2a in contact with each other. Every other one of the upper end portions is inclined toward the outside of the water pipe array 2 by a predetermined angle θ, and the vertical water pipes 2a and the inclined water pipes 2a are alternately arranged. As shown in FIG. 3, a vertically long inverted triangular combustion gas outlet 12 having an upper end portion wider than the lower end portion is formed, and a space surrounded by a plurality of water pipes 2a is used as a combustion chamber 3. Is.

  As shown in FIG. 1, the upper header 4 and the lower header 5 are formed in an annular shape having a hollow structure having a rectangular cross-section, and the headers 4 and 5 have the water pipes 2 a of the water pipe array 2 respectively. The upper end and the lower end are connected so as to communicate with each other.

  Although not shown, a steam pipe and a steam separator are connected to the upper header 4, and a return pipe from the steam separator, a water supply pipe and a water pump are connected to the lower header 5. Etc. are connected.

  As shown in FIGS. 1 and 2, the smoke chamber cover 7 is formed in a tubular shape larger than the outer diameter of the annular water pipe array 2, and is arranged outside the water pipe array 2 concentrically with the water pipe array 2. Thus, an annular combustion gas passage 6 is formed between the row of water pipes 2. The combustion gas passage 6 is connected to the combustion chamber 3 by a combustion gas outlet 12 formed between the water pipes 2a of the water pipe array 2.

  Further, a smoke passage 13 communicating with the lower end of the combustion gas passage 6 (the downstream end of the combustion gas passage 6) is connected to the lower end of the smoke chamber cover 7.

  As shown in FIG. 1, the burner 8 is disposed above the combustion chamber 3 and blows fuel and combustion air into the combustion chamber 3 to generate combustion gas G. The flow rate, temperature and pressure of the combustion gas G fluctuate according to the fuel flow rate controlled by the boiler pressure state.

  As shown in FIGS. 1 to 4, the heat-absorbing fins 9 are formed of a metal plate such as a steel plate in an appropriate shape, and are located on the downstream side of the combustion gas passage 6 where the temperature of the combustion gas G decreases. The water pipe 2a is provided in a multi-stepped shape in the vertical direction at a fixed mounting pitch P in a portion facing the combustion gas passage 6.

  The baffle plate 10 swirls the combustion gas G flowing in the combustion gas passage 6 (combustion force) so that the heat transfer surfaces of the heat absorbing fins 9 provided in the water pipes 2a in multiple stages in the vertical direction can be effectively used. The gas G provides a force that flows in the annular combustion gas passage 6 along the circumferential direction, and the heat absorbing fins 9 of the water pipe 2a adjacent to the shape of the heat absorbing fins 9 are attached in the vertical direction. It is removably attached to the heat absorbing fins 9 using the pitch P or the like.

  That is, the baffle plate 10 is formed of a metal plate such as a steel plate having elasticity in a plane shape in an arc shape, and as shown in FIGS. 4 and 5, the heat absorbing fins 9 are formed in the center of the inside of the baffle plate 10. A recessed portion 10a is provided so that it can be freely inserted and removed in a state of intersecting with each other, and both ends of the baffle plate 10 are elastically connected to the heat absorbing fins 9 that are vertically shifted by at least one pitch P between the adjacent water pipes 2a. Guide portions 10b that are pressed against and fixed to are respectively provided.

  The overall shape and size of the baffle plate 10, the shape and size of the recess 10a, the shape and size of the guide portion 10b, and the like are the shape, thickness and size of the heat absorbing fins 9, the heat absorption of the baffle plate 10. It is determined by the mounting angle of the heat-absorbing fin 9 and the mounting pitch P of the heat-absorbing fin 9 in the vertical direction.

  The length L1 of the central portion of the baffle plate 10 in the depth direction (the vertical direction of the baffle plate 10 shown in FIG. 5) is defined by the concave portion 10a as shown in FIG. When the outer peripheral edge portion 10d of the baffle plate 10 is brought into contact with the inner peripheral surface of the cylindrical smoke chamber cover 7 while being fitted in a state of intersecting the center position of the heat absorbing fin 9 shown in the left-right direction). The inner peripheral edge portion 10c adjacent to the recess 10a is set so as not to hit the outer peripheral surface of the water pipe 2a.

  Further, the width W of the recess 10a of the baffle plate 10 is set at the center position in the width direction of the heat absorbing fin 9 provided in the water pipe 2a in the vertical posture (left and right direction of the heat absorbing fin 9 shown in FIG. 4). When fitted in the intersecting state, the guide portions 10b formed at both ends of the baffle plate 10 are pressed and fixed to the heat absorbing fins 9 that are vertically shifted by one pitch P of the adjacent water pipes 2a in the inclined posture. Is set. For example, in a state where the recess 10a of the baffle plate 10 intersects the center position in the width direction of the heat absorbing fins 9 provided on the water pipe 2a in the vertical posture with the right end portion of the baffle plate 10 higher than the left end portion. When fitted, the guide portion 10b on the right side of the baffle plate 10 elastically abuts the lower surface of the heat absorbing fins 9 on the upper side of one pitch P of the adjacent inclined water pipes 2a, and on the left side of the baffle plate 10. The guide portions 10b are elastically brought into contact with the lower surface of the heat absorbing fins 9 (or the upper surface of the heat absorbing fins 9) located one pitch P below the adjacent water pipes 2a (FIG. 2). ~ See Figure 4).

  Further, as shown in FIG. 5, the guide portions 10b formed at both ends of the baffle plate 10 are arranged at the inner peripheral edges of both ends of the baffle plate 10 in the width direction (the vertical direction of the baffle plate 10 shown in FIGS. 4 and 5). ) Is formed by providing a notch 10e along the), and has a band shape having an elastic force. As shown in FIG. 4, the length L2 of the guide portion 10b intersects the recess 10a of the baffle plate 10 at the center position in the width direction of the heat absorbing fin 9 (left and right direction of the heat absorbing fin 9 shown in FIG. 4). When the outer peripheral edge portion 10d of the baffle plate 10 is brought into contact with the inner peripheral surface of the cylindrical smoke chamber cover 7, the heat absorption provided on the adjacent water pipes 2a in the left and right inclined postures. Is reliably caught by the heat-use fins 9 (the heat-absorption fins 9 on the upper side of the 1 pitch P and the heat-absorption fins 9 on the lower side of the 1-pitch P), and the tip of the guide portion 10b does not contact the outer peripheral surface of the inclined water pipe 2a. Is set.

  Further, the baffle plate 10 is formed in an arc shape in which the outer peripheral edge portion 10d thereof comes into contact with the inner peripheral surface of the cylindrical smoke chamber cover 7 in a surface contact state, and is attached to the heat absorbing fin 9 to form a cylindrical shape. When the water pipe array 2 is covered with the smoke chamber cover 7, the outer peripheral edge of the baffle plate 10 comes into contact with the inner peripheral surface of the smoke chamber cover 7, and the smoke chamber cover 7 holds and fixes it at an appropriate position. (See FIG. 4).

  Thus, the above-mentioned baffle plate 10 is fitted in such a manner that the concave portion 10a thereof intersects the center position in the width direction of the desired heat absorbing fin 9 provided in the water pipe 2a, and the right guide portions 10b are adjacent to each other. The water pipe 2a (the water pipe 2a on the right side of the water pipe 2a facing the recess 10a) is elastically brought into contact with the lower end surface of the heat absorbing fin 9 that is displaced upward by one pitch P, and the left guide portion 10b is adjacent to the water pipe. 2a (the water pipe 2a on the left side of the water pipe 2a facing the recess 10a) can be attached to and detached from the heat absorbing fin 9 by elastically abutting the lower end surface of the heat absorbing fin 9 which is displaced downward by one pitch P. (See FIGS. 2 to 4).

  After the baffle plate 10 is attached to the heat absorbing fins 9, the outer side of the water pipe array 2 is covered with a cylindrical smoke chamber cover 7, and the outer peripheral edge portion 10d of the baffle plate 10 is covered with the smoke chamber cover 7 with the water pipe array 2. By pressing it to the side, it is held and fixed at an appropriate position.

  Furthermore, the baffle plate 10 is removably attached to the plurality of heat absorbing fins 9 in the vertical direction of the water pipe 2a at a predetermined pitch, and is also attached to the annular combustion gas passage 6 at a predetermined pitch in the circumferential direction. It is arranged and detachably attached to the heat absorbing fin 9.

  In this embodiment, four baffle plates 10 are attached to the heat absorbing fins 9 of the water pipe 2a at a constant pitch in the vertical direction. Further, 13 baffle plates 10 are arranged in the annular combustion gas flow path 6 at a constant pitch in the circumferential direction, and the central portion of each baffle plate 10 is attached to the water pipe 2a in the vertical posture. Therefore, the baffle plates 10 arranged in an annular shape are arranged in four stages in the vertical direction in the annular combustion gas passage 6. The baffle plates 10 in each stage are arranged on the same plane.

  According to the small once-through boiler 1 configured as described above, the combustion gas G generated by the combustion of the burner 8 is inverted in the lower portion of the combustion chamber 3 to perform reverse combustion, and the combustion gas outlet 12 forms an annular combustion gas. It flows into the upstream side portion of the flow channel 6 (the upper part of the combustion gas flow channel 6).

  The combustion gas G that has flowed into the upstream side portion of the combustion gas flow path 6 flows in the combustion gas flow path 6 from the upper side to the lower side along the longitudinal direction of the water pipe array 2, and most of the combustion gas G is a plurality of baffles. While colliding with the plate 10 and changing the direction in the circumferential direction of the water tube array 2 to uniformly swirl in the annular combustion gas passage 6, the heat transfer surface of the heat absorbing fin 9 (the upper surface of the heat absorbing fin 9). And the lower surface), and flows in the combustion gas passage 6 to the downstream side (the lower portion of the combustion gas passage 6).

  The combustion gas G flowing in the annular combustion gas passage 6 is sufficiently absorbed by the plurality of water pipes 2 a and the heat absorbing fins 9, and then discharged from the flue 13.

  In the small once-through boiler 1 described above, the heat absorbing fins 9 provided in multiple stages on the water pipe 2a utilize the shape of the heat absorbing fins 9 and the vertical mounting pitch P of the heat absorbing fins 9 of the water pipe 2a that are adjacent to each other. Since the baffle plate 10 that gives a swirling force to the combustion gas G flowing in the annular combustion gas flow path 6 is detachably attached, a gas guide for swirling the combustion gas, like a conventional small once-through boiler, is provided. It is not necessary to fix the plate to the water pipe or the like by welding, and the baffle plate 10 that gives a swirling force to the combustion gas G in the annular combustion gas passage 6 can be easily and easily attached to the heat absorbing fins 9. The baffle plate 10 makes it possible to easily obtain a swirling flow in which the heat transfer surface of the heat absorbing fin 9 can be effectively used.

  Further, in the small once-through boiler 1, the baffle plate 10 is formed of an elastic metal plate, and the baffle plate 10 is attached to the heat absorbing fins 9 by utilizing its elastic force. It is possible to prevent the fins 9 from falling off, and it is possible to reliably and satisfactorily provide the combustion gas G with a swirling flow.

  Further, in the small once-through boiler 1, the baffle plate 10 is detachably attached to the plurality of heat absorbing fins 9 in the vertical direction of the water pipe 2a at a predetermined pitch, and is circular in the annular combustion gas passage 6. Since they are arranged at a predetermined pitch in the circumferential direction and are detachably attached to the heat absorbing fins 9, by changing the number of baffle plates 10 mounted in the vertical direction or the number of baffle plates 10 mounted in the circumferential direction, The amount of heat absorption can be easily adjusted.

  Further, in the small-sized once-through boiler 1, the outer peripheral edge of the baffle plate 10 abuts on the inner peripheral surface of the smoke chamber cover 7, and the baffle plate 10 is pressed by the smoke chamber cover 7 toward the water pipe 2a side and held and fixed in an appropriate position. Therefore, it is possible to reliably prevent the baffle plate 10 from shifting or dropping with respect to the heat absorbing fins 9.

  Table 1 below shows the case where the present invention is applied to the small-sized once-through boiler 1 having a generated heat amount of 313 kW (the small once-through boiler 1 of the present invention provided with the baffle plate 10) and the case where the present invention is not applied (the baffle plate 10 is not provided. It shows the test data of a conventional small once-through boiler.

  As is clear from Table 1, the small-sized once-through boiler 1 of the present invention with the baffle plate 10 attached has a higher heat absorption amount and higher boiler efficiency than the conventional small-sized once-through boiler without the baffle plate 10. I see.

  By the way, when the baffle plate 10 is attached, the furnace pressure may increase and proper combustion may not be possible due to the blowing function of the burner 8. In this case, therefore, the baffle plate should be checked by balancing the boiler efficiency and the furnace pressure. It suffices to select 10 sheets.

  Although the number of baffle plates 10 mounted in the vertical direction is four in the above embodiment, the number of baffle plates 10 mounted in the vertical direction is not limited to that in the above embodiment. Any number of sheets may be used as long as the swirling flow can be given to the combustion gas G flowing through the combustion gas passage 6.

  Further, in the above-described embodiment, the vertical mounting pitch of the baffle plate 10 is constant, but in other embodiments, the vertical mounting pitch of the baffle plate 10 is set to the combustion gas G as shown in FIG. The temperature may be narrowed toward the downstream side of the combustion gas passage 6 where the temperature becomes low, and the heat absorption amount may be adjusted to be uniform.

  Further, in the above-described embodiment, the recess 10a of the baffle plate 10 is attached to the heat absorbing fins 9 provided on each water pipe 2a of the water pipe array 2 in the vertical posture, and the guide portion 10b of the baffle plate 10 is inclined in the water pipe. The heat absorbing fins 9 provided on the water absorbing fins 2a are elastically engaged with each other, but in another embodiment, the recesses 10a of the baffle plate 10 are provided on the water pipes 2a in the inclined posture of the water pipe array 2 for heat absorbing. The fins 9 may be attached to the fins 9, and the guide portions 10b of the baffle plate 10 may be attached to the heat absorbing fins 9 provided on the vertical water pipe 2a. In this case, it is necessary to change the overall planar shape of the baffle plate 10 according to the shape of the cross section of the combustion gas passage 6.

  Further, in the above embodiment, 13 baffle plates 10 are arranged in the annular combustion gas flow path 6 at a constant pitch in the circumferential direction, but the number of baffle plates 10 mounted in the circumferential direction is The number is not limited to that of the above embodiment, and any number may be used as long as the swirling flow can be given to the combustion gas G flowing through the combustion gas passage 6. If the number of baffle plates 10 mounted in the circumferential direction is reduced, the swirling force of the combustion gas G is reduced and the heat absorption amount is reduced. Therefore, the amount of heat absorption can also be adjusted by adjusting the number of baffle plates 10 mounted in the circumferential direction.

  Further, in the above embodiment, the baffle plate 10 is attached to the heat absorbing fins 9 of the water pipe array 2 in which the water pipes 2a in the vertical posture and the water pipes 2a in the inclined posture are alternately arranged, but in other embodiments. The baffle plate 10 may be attached to the heat absorbing fins 9 of the water pipe array 2 shown in FIGS. 7 to 18, or, although not shown, a plurality of water pipes 2a are arranged in a circumferential shape, The baffle plate 10 may be attached to the heat absorbing fins 9 of the water pipe array 2 formed by hermetically connecting the adjacent water pipes 2a with each other by a vertically extending strip-shaped fin member.

1 is a small once-through boiler 2 is a water pipe array 2a is a water pipe 3 is a combustion chamber 4 is an upper pipe 5 is a lower pipe 6 is a combustion gas flow passage 7 is a smoke chamber cover 8 is a burner 9 is a heat absorbing fin 10 is a baffle plate 10a is a concave portion 10b is a guide portion G is a combustion gas P is a heat absorbing fin mounting pitch

Claims (5)

  An annular water pipe array in which a plurality of water pipes are circumferentially arranged and a space surrounded by the water pipes serves as a combustion chamber, and an annular upper part connected to the upper and lower ends of each water pipe of the water pipe array in communication with each other. A tubular smoke chamber cover that forms an annular combustion gas flow path that communicates with the combustion chamber between the pipe header and the lower pipe header, the outer side of the water pipe array, and the water pipe array, and the upper part of the combustion chamber In the small once-through boiler, the burner and a plurality of heat absorbing fins provided in multiple stages in the vertical direction at least in a portion of the water pipe on the downstream side of the combustion gas flow passage facing the combustion gas flow passage are provided. The baffle plate that gives a swirling force to the combustion gas flowing in the combustion gas flow path in a tilted posture is used for the cooling fin by utilizing the shape of the heat absorbing fin and the mounting pitch of the heat absorbing fin of the adjacent water pipe in the vertical direction. Small flow-through characterized by being detachably attached Ira.   The baffle plate is formed of an elastic metal plate in a planar shape in an arc shape, and a concave portion is provided in an inner center portion of the baffle plate so as to be freely inserted and removed while intersecting with the heat absorbing fins. The guide parts that are pressed and fixed to the heat absorbing fins that are vertically shifted at least one pitch from the adjacent water pipes are provided at both ends of the baffle plate, respectively. Small once-through boiler.   The baffle plate has a recess formed in the center of the inside of the baffle plate fitted and locked in a state of intersecting the heat absorbing fins, and guide portions formed at both ends of the baffle plate are connected to adjacent water pipes. An inclined position in which one guide part is higher than the other guide part in the heat absorbing fins while being elastically locked to the heat absorbing fins that are displaced at least one pitch up and down by the elastic force of the baffle plate itself. Small once-through boiler according to claim 2, characterized in that it is mounted with.   The baffle plate is detachably attached to a plurality of heat absorbing fins in a vertical direction of the water pipe at a predetermined pitch, and is arranged in an annular combustion gas passage at a predetermined pitch in the circumferential direction to absorb heat. The small once-through boiler according to any one of claims 1, 2 and 3, wherein the small once-through boiler is detachably attached to a fin for use.   The outer peripheral edge of the baffle plate is in contact with the inner peripheral surface of the smoke chamber cover, and the baffle plate is held and fixed in an appropriate position by the smoke chamber cover. The small once-through boiler according to claim 4.